Does a SIM card consist of only Flash memory or is there a microprocessor inside as well?

  • My answer was incorrect. It has been updated. – julian Mar 22 '17 at 13:50
  • How does this related to reverse engineering? – phuclv Mar 24 '17 at 9:19
  • @SDsolar first post or not isn't an explanantion for it on this site. It's off topic and this should be on electronics.stackexchange.com – phuclv Mar 25 '17 at 3:58
  • 2
    I'm voting to close this question as off-topic because it is about regular hardware usage. – perror Mar 25 '17 at 8:34
  • This question can be closed if that's the wish of the majority. I don't have any problem because I've already asked the question at the right forum (as was suggested). – Vishal Sharma Mar 25 '17 at 10:05


in fact many SIMs do contain a microprocessor for extra functionality (see SIM Application Toolkit).

Thank you Igor Skochinsky for the correction.

According to Karsten Nohl's presentation "Mobile Network Attack Evolution", SIM cards contain an embedded real-time operating system, a filesystem and a Java VM :

Presentation slide 1

Slide 2

Here is a direct link to the presentation: https://www.slideshare.net/phdays/140521karsten-nohl-phdmobileattackevolution-35161629

See also: 4G Security: Hacking USB Modem and SIM Card via SMS

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  • Excellent information. I recently bought a $10 gadget called a "SIM card reader" but it shows nothing when I plug it into the USB port. I suppose it must require some fancy software to make all this work, eh? – SDsolar Mar 24 '17 at 8:10
  • I don't know but I'm sure that someone else here will. Maybe post a question about it? – julian Mar 24 '17 at 14:20
  • Thanks for the info. However I'd like to know a few more things: 1. Since which generation did the SIM cards start to have a microprocessor? I mean, was it after 2G, 3G or 4G? 2. Mainly which microprocessor is used in the SIMs? – Vishal Sharma Mar 25 '17 at 3:18
  • I couldn't find anywhere explicitly written that SIM cards contain microprocessor. Why do you think we don't have info about the microprocessors being used in our modern SIM cards like we have in the case of smartphones? – Vishal Sharma Mar 25 '17 at 3:39

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